I have been writing RPGs a lot and I would say it's an overkill (unless you are making an MMORPG, but that's a different kind of beast). To be clear, I'm a great fan of SQL and I use it a lot in my games, I just don't find it practical for a single player RPG for reasons listed below.
You have these fixed things: skills, status effects, spells. All of them should be hardcoded. These rely too much on code, so from my experience treating them like data is unpractical. These are simply too unique from each other to represent them as data.
You have these flexible things: items, monsters, quests/dialogues, map. Of them map has to be a separate non SQL structure (for numerous reasons, for starters try doing pathfidning using SQL
), quests are best implemented as a scripting language. Which leaves only items and monsters that are reasonable to be made via SQL. But since you already need a scripting language for quests and dialogues you could simply add one "defenie" script which defines all items and monsters.